Global trends and advances in pediatric bronchiolitis treatment in the last two decades: a bibliometric analysis

Abstract

Background

Bronchiolitis, a leading respiratory disease in infants, causes substantial global morbidity. This is the first study to employ bibliometric analysis to explore global trends and progress in pediatric bronchiolitis treatment, addressing a previously unexamined gap.

Methods

A comprehensive literature search was conducted in the Web of Science Core Collection on January 31, 2025, encompassing publications between 2004 and 2024. The bibliometric analysis utilized VOSviewer, CiteSpace, and the R package “bibliometrix” for data visualization, network analysis, and the identification of research hotspots.

Results

A total of 1,370 articles were included in this study. The United States emerged as the leading contributor with 403 articles, followed by China [101] and the United Kingdom [79]. The most prolific institutions included Assistance Publique-Hôpitaux de Paris and Harvard University. Notable journals such as Pediatrics and Pediatric Pulmonology were identified as key platforms for high-impact authors, with prominent figures such as Babl Franz E. making substantial contributions to the field. Keyword analysis indicated five thematic clusters, including risk stratification-based therapy, anti-respiratory syncytial virus therapy, respiratory support, clinical-practice guideline, and clinical trials. Emerging topics included “epidemiology”, “prevention”, “infections”, “oxygen therapy”, and “guideline”, which were more prominently featured in recent years.

Conclusions

Research on pediatric bronchiolitis over the past 20 years has focused on optimizing treatment, particularly respiratory support, anti-respiratory syncytial virus therapy, and guideline-based care. Emerging trends emphasize prevention, infection control, and high-quality clinical trials to improve patient outcomes.

Highlight box.

Key findings

• Analysis of 1,370 articles (2004–2024) reveals the United States, China, and the United Kingdom as leading contributors, with research concentrated in high-impact journals like Pediatrics. Key research themes include risk stratification-based therapy, anti-respiratory syncytial virus (RSV) therapy, respiratory support, clinical-practice guideline, and clinical trials.

What is known and what is new?

• Prior knowledge centered on bronchiolitis management, such as supportive oxygen therapy.

• This first bibliometric study indicates a potential shift in research focus toward prevention strategies involving respiratory syncytial virus antibodies for bronchiolitis.

What is the implication, and what should change now?

• The field is evolving from basic management toward prevention, infection control, and guideline implementation. Future efforts should prioritize high-quality trials to optimize therapies and translate evidence into improved clinical practice and outcomes.

Introduction

Bronchiolitis is a common acute lower respiratory tract infection (ALRTI) in infants and young children, primarily affecting children aged under 2 years (1). The pathogenesis of bronchiolitis primarily involves respiratory syncytial virus (RSV), which is responsible for approximately 80% of cases in infants under six months of age. Other common pathogens, such as rhinoviru, influenza viruses types I–III, adenoviruses, and metapneumovirus, have also been implicated. These infectious agents trigger innate immune responses, promote apoptosis and necrosis, and induce excessive mucus production (2,3). Identified risk factors for bronchiolitis include attendance at daycare, absence of breastfeeding, exposure to parental smoking, low birth weight, and age under 12 months (4). Globally, approximately 150 million new cases of bronchiolitis are reported annually, with 2–3% requiring hospitalization (1), presenting a huge clinical burden. Therefore, effective prevention and treatment strategies for bronchiolitis are crucial for managing this population.

To date, no pharmacological therapy has been established as effective for bronchiolitis in the short- or long-term. Current management therefore remains primarily supportive, which may include oxygen therapy, hydration, and in certain cases, interventions such as hypertonic saline nebulization (5). These interventions, especially for young children, improve airway patency, blood oxygen saturation (SpO₂), and feeding tolerance. In terms of pharmacological treatment, ribavirin, an agent targeting respiratory syncytial virus, has been shown to effectively alleviate clinical symptoms when administered via precise delivery methods, such as continuous nebulization (6), while the use of bronchodilators and corticosteroids remains controversial (7). Furthermore, as medical technology continues to advance, treatment approaches are increasingly stratified according to illness severity and patient risk factors. Conducting systematic bibliometric analyses has therefore become essential for identifying research trends and guiding future directions in this field.

Bibliometrics, which uses mathematical and statistical methods to quantitatively analyze scientific literature, is essential for uncovering the development, current status, and research trends in various academic fields (8). For instance, Nievas-Soriano et al. conducted a bibliometric analysis of pediatric bronchiolitis literature spanning from 1980 to 2022 using the Scopus database, identifying key future research priorities, especially in hospital treatment and clinical studies (9). However, no bibliometric studies have specifically focused on treatment strategies for pediatric bronchiolitis. This first study seeks to address this gap by providing a comprehensive bibliometric analysis specifically centered on treatment-related research in pediatric bronchiolitis, thereby offering valuable insights for researchers, clinicians, and policymakers. We present this article in accordance with the BIBLIO reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1-2763/rc).

Methods

Search strategies and data collection

A comprehensive literature search was performed in the Web of Science Core Collection (WoSCC), a multidisciplinary database recognized for its complete citation network and broad scholarly coverage (10), to explore studies on pediatric bronchiolitis treatment from 2004 to 2024. The WoSCC provides access to high-quality academic publications across a wide range of disciplines, ensuring the inclusion of relevant studies from reliable sources. The search strategy employed was: (TS = (((Bronchiolitis OR Bronchiolitides) NOT “bronchiolitis obliterans”) AND (child* OR adolescen* OR kids OR preteen* OR Infant* OR infanc* OR pediatr* OR paediatr* OR teenage* OR preteen* OR kindergarten OR preschool* OR “school-age”))) AND TS = (Treatment* OR therap*) (9). Only English-language literature classified as “articles” and published between January 1, 2004, and December 31, 2024, was included in this analysis. The exclusion criteria encompassed non-article literature, including review articles, letters, meeting abstracts, conference proceedings, editorial materials, and early access publications, as well as studies unrelated to the research topic.

The literature search was performed on January 15, 2025, to ensure the timeliness of the retrieved data. Bibliographic information was exported in “Full record and cited references” and “plain text” formats, ensuring the comprehensive collection of data for analysis. The collected data included publication and citation counts, author details, journal titles, institutional and regional affiliations, keywords, and publication counts.

Statistical analysis

Three bibliometric tools were applied for data visualization and analysis: VOSviewer (v1.6.20), CiteSpace (v6.3.R1), and the R package “bibliometrix” (v4.3.3). VOSviewer was used to map author collaboration, keyword co-occurrence, and institutional networks, offering a visual representation of academic collaboration patterns (11). CiteSpace supported the detection of emerging research trends and keyword bursts (12), with the analysis covering the period 2004–2024. Keywords were defined as nodes, retaining the top 5 keywords per time slice. Network pruning was conducted using the Pathfinder algorithm, and the resulting networks were merged for clarity. The R package “bibliometrix” facilitated trend mapping, ranking analyses, and tracking of publication and citation metrics across authors, institutions, and countries. It also enabled the generation of longitudinal charts to illustrate the evolution of the research domain (13). Several bibliometric indices were calculated to assess academic impact: the h-index, which reflects both productivity and citation performance (14); the g-index, which emphasizes highly cited works; and the m-index, which adjusts the h-index for career duration (15). Journals were also categorized according to Journal Citation Reports (JCR) based on their impact factor (IF)—a measure of average citations per published article—to evaluate their relative influence in the field (16).

Results

Trends in publication and citation analysis

The literature screening process, as illustrated in Figure 1A, comprised several rigorous stages. An initial systematic search of the WoSCC database yielded 2,469 records. Following the application of predefined inclusion and exclusion criteria, the dataset was refined to 1,370 eligible English-language publications dated between January 1, 2004, and December 31, 2024. These studies were authored by 8,268 researchers from 6,021 institutions across 90 countries or regions. The publications were distributed across 402 academic journals and collectively cited 27,120 references. Detailed information on the literature analyzed in this study is presented in table available at https://cdn.amegroups.cn/static/public/jtd-2025-1-2763-1.xlsx.

Figure 1.

Data screening and publication trends. (A) Flowchart of the data screening process. (B) Annual number of publications from 2004 to 2024.

The field exhibited remarkable expansion dynamics, growing from 34 annual publications in 2004 to 109 in 2024, reflecting a compound annual growth rate of 6%. Temporal analysis revealed three distinct phases of research activity: an initial development phase (2004–2010), characterized by fewer than 50 publications annually; a subsequent period of steady growth; and a rapid expansion phase beginning in 2019, peaking at 123 publications in 2021. Linear regression analysis of annual publication counts yielded the predictive model Y=4.3468x+17.424, demonstrating strong explanatory power with R²=0.8194 (Figure 1B).

Analysis of leading countries

As detailed in Table 1, the United States demonstrated unequivocal scholarly leadership across all metrics. With 403 articles (29.4% of total output), the United States significantly outpaced China (101, 7.4%) and the United Kingdom (79, 5.8%) in articles volume. The United States demonstrated a marked dominance in research impact, as reflected by its total citation count (TC) of 14,315—surpassing that of the United Kingdom [4,199] by over threefold and that of Australia [2,688] by nearly fivefold. Additionally, the United States led in total publication output (TP), with 1,779 articles, significantly outpacing Australia [597] and France [470], which ranked second and third, respectively. Notably, the United States further solidified its preeminence in collaborative scholarship, contributing 55 multi-country publications (MCP), surpassing Australia [35] and the United Kingdom [29] (Figure 2A). Analysis of international networks revealed a robust collaboration landscape involving 55 nations (minimum publication threshold =3 articles). The United States anchored this global network with the highest link strength [253], followed by the United Kingdom [225] and Australia [151] (Figure 2B).

Table 1. Publication and citation profiles of leading countries.

Country	Articles	Freq	SCP	MCP	MCP_ratio	TP	TP_rank	TC	TC_rank	Average citations
United States	403	0.294	348	55	0.136	1,779	1	14,315	1	35.5
China	101	0.074	89	12	0.119	432	4	1,210	8	12
United Kingdom	79	0.058	50	29	0.367	371	7	4,199	2	53.2
Australia	78	0.057	43	35	0.449	597	2	2,688	3	34.5
Spain	74	0.054	62	12	0.162	372	6	1,735	6	23.4
France	69	0.050	54	15	0.217	470	3	1,598	7	23.2
Italy	65	0.047	58	7	0.108	298	8	1,000	9	15.4
Canada	57	0.042	34	23	0.404	392	5	2,144	4	37.6
Turkey	42	0.031	40	2	0.048	121	12	588	13	14
Netherlands	39	0.028	28	11	0.282	193	9	1,852	5	47.5
Brazil	38	0.028	34	4	0.105	146	10	737	11	19.4
Israel	29	0.021	23	6	0.207	105	14	464	15	16
Finland	27	0.020	19	8	0.296	124	11	815	10	30.2
Japan	25	0.018	21	4	0.160	87	16	364	16	14.6
Germany	18	0.013	13	5	0.278	95	15	220	20	12.2
Belgium	16	0.012	10	6	0.375	69	17	594	12	37.1
Colombia	14	0.010	9	5	0.357	43	24	99	27	7.1
Norway	13	0.009	10	3	0.231	68	18	246	19	18.9
Switzerland	12	0.009	9	3	0.250	55	22	320	17	26.7
Korea	10	0.007	8	2	0.200	59	20	169	23	16.9

Articles, includes only publications from corresponding authors; Average citations, average citations per publication; Freq, frequency of total publications; MCP, multi-country publications; MCP_ratio, ratio of MCP to total publications; SCP, single-country publications; TC, total citations; TC_rank, rank by citation count; TP, total publications; TP_rank, rank by publication count.

Figure 2.

Global publication distribution and collaboration. (A) Distribution of corresponding authors by country. (B) Network map of international collaboration. MCP, multi-country publications; SCP, single-country publications.

Analysis of institutions

Quantitative analysis of institutional contributions revealed distinct patterns of research output and collaboration. The top 10 productive institutions were displayed in Figure 3A. The Assistance Publique-Hôpitaux de Paris (APHP) emerged as the most prolific institution with 106 publications, narrowly leading Harvard University [104] and the University System of Ohio [100]. Network analysis using VOSviewer mapped inter-institutional collaboration dynamics among 197 institutions meeting the minimum threshold of three collaborative articles (Figure 3B). The University of Melbourne demonstrated the strongest collaborative ties (link strength =252), followed by the Royal Children’s Hospital (link strength =240) and the University of Auckland (link strength =226).

Figure 3.

Institutional contributions and collaborations. (A) Top 10 institutions by number of publications. (B) Network map of institutional collaboration. (C) Author collaboration network.

Analysis of authors

The field engaged 8,268 authors exhibiting substantial heterogeneity in research output and influence. High-impact scholars were identified through h-index analysis (Table 2), Babl Franz E. and Schibler Andreas jointly led in h-index [14], demonstrating sustained impact across publications, followed by Korppi Matti (h-index =13). Babl Franz E. dominated publication volume (TP =23), closely followed by Dalziel Stuart R. and Oakley Ed (TP =19 each). In term of TC, Schibler Andreas emerged as the most cited author (TC =1,071), nearly doubling the output of second-ranked Ramilo Octavio (TC =757). Collaboration analysis of 220 authors (minimum three articles) uncovered tightly interconnected research clusters (Figure 3C). Babl Franz E. had the highest number of collaborations with other authors (link strength =180), followed by Dalziel Stuart R. (link strength =156) and Oakley Ed (link strength =131).

Table 2. Publication and citation profiles of high-impact authors.

Authors	H_index	G-index	M-index	PY_start	TP	TP_frac	TP_rank	TC	TC_rank
Babl Franz E.	14	23	0.88	2010	23	2.10	1	746	5
Schibler Andreas	14	18	1.17	2014	18	2.23	5	1,071	2
Korppi Matti	13	17	0.68	2007	18	3.85	4	299	34
Camargo Carlos A. Jr.	12	16	0.67	2008	16	2.11	6	488	17
Oakley Ed	12	19	0.75	2010	19	1.60	3	660	8
Dalziel Stuart R.	11	19	1.22	2017	19	1.63	2	690	6
Piedra Pedro A.	11	11	0.92	2014	11	1.33	12	532	16
Mansbach Jonathan M.	10	14	0.56	2008	14	1.88	8	408	24
Franklin Donna	9	14	0.82	2015	14	1.44	7	562	13
Milesi Christophe	9	12	0.50	2008	12	1.27	10	656	9
Ramilo Octavio	9	9	0.53	2009	9	1.34	23	757	4
Espinola Janice A.	8	9	0.47	2009	9	1.18	16	231	38
Jartti Tuomas	8	9	0.40	2006	9	1.07	20	488	17
Johnson David W.	8	9	0.47	2009	9	0.84	21	410	22
Neutze Jocelyn	8	11	0.50	2010	11	0.76	11	534	15
Schuh Suzanne	8	11	0.42	2007	11	0.96	13	409	23
Borland Meredith L.	7	12	0.88	2018	12	1.11	9	241	36
Casola Antonella	7	7	0.47	2011	7	1.02	36	345	28
Garofalo Roberto P.	7	8	0.47	2011	8	1.07	29	335	30
Klassen Terry P.	7	7	0.41	2009	7	0.89	39	465	20

G_index, gives greater weight to highly cited articles; H_index, measures both journal productivity and citation impact; M_index, represents the h-index normalized by years since first publication; PY_start, first publication year of the journal; TC, total citations; TC_rank, citation ranking; TP, total publications; TP_frac, proportion of total publications; TP_rank, publication ranking.

Analysis of journals

Research in this field was disseminated across 402 academic journals, with the top 20 ranked by h-index presented in Table 3. Notably, Pediatrics demonstrated the highest h-index (32, IF =6.2), significantly exceeding Pediatric Pulmonology (h-index =25, IF =2.7) and the Journal of Pediatrics (h-index =20, IF =3.9). In terms of TPs, Pediatric Pulmonology led with 78 articles, followed by Pediatrics with 63 articles and the European Journal of Pediatrics with 35 articles. Pediatrics also exhibited a remarkable citation advantage (TC =3,346), nearly tripling the citation counts of the Journal of Pediatrics (TC =1,338) and Pediatric Pulmonology (TC =1,244).

Table 3. Bibliometric indicators of high-impact journals.

Journal	H_index	IF	JCR_quartile	PY_start	TP	TP_rank	TC	TC_rank
Pediatrics	32	6.2	Q1	2004	63	2	3,346	1
Pediatric Pulmonology	25	2.7	Q2	2004	78	1	1,244	4
Journal of Pediatrics	20	3.9	Q1	2004	28	6	1,338	3
PLOS ONE	16	2.9	Q1	2008	30	4	599	14
European Journal of Pediatrics	15	3	Q1	2005	35	3	481	20
Pediatric Infectious Disease Journal	15	2.9	Q1	2004	28	7	1163	5
Archives of Disease in Childhood	14	4.3	Q1	2004	23	11	848	10
Pediatric Critical Care Medicine	13	4	Q1	2007	25	9	514	16
Pediatric Emergency Care	13	1.2	Q3	2004	27	8	334	26
Respiratory Care	13	2.4	Q2	2011	24	10	352	24
Acta Paediatrica	12	2.4	Q1	2009	28	5	395	23
Journal of Infectious Diseases	12	5	Q1	2006	16	17	982	8
European Respiratory Journal	11	16.6	Q1	2004	11	21	560	15
Journal of Virology	11	4	Q2	2005	11	22	803	11
BMC Pediatrics	10	2	Q2	2010	17	14	230	35
Journal of Paediatrics and Child Health	10	1.6	Q2	2009	21	12	324	27
Jama Pediatrics	9	24.7	Q1	2013	9	29	261	33
Intensive Care Medicine	8	27.1	Q1	2005	8	32	703	13
Journal of Allergy and Clinical Immunology	8	11.4	Q1	2004	8	34	730	12
Journal of Hospital Medicine	8	2.4	Q1	2008	16	16	125	60

H_index, evaluates journal productivity and citation impact; IF, impact factor (2023), reflecting average recent citations per article; JCR_quartile, Journal ranking in 2023 Journal Citation Reports (Q1, top 25%; Q2, 26–50%; Q3, 51–75%; Q4, 76–100%); PY_start, first year of publication; TC, total citations; TC_rank, citation rank; TP, total publications; TP_rank, publication rank.

Co-occurrence analysis of 121 journals, applying a minimum occurrence threshold of 3, identified three core journals with the highest total link strengths: Pediatrics [722], Pediatric Pulmonology [570], and the Journal of Pediatrics [361] (Figure 4A). In contrast, coupling analysis of the same journal set, with a minimum coupling threshold of 3, showed a different centrality pattern: Pediatric Pulmonology exhibited the strongest connections [27,592], followed by Pediatrics [24,662] and the European Journal of Pediatrics [13,487] (Figure 4B).

Figure 4.

Network analysis of journals. (A) Journal co-occurrence network. (B) Journal coupling network.

Analysis of co-occurring keywords

Keyword analysis provided valuable insights into the research hotspots and evolving trends within the field. Table 4 presented the top 20 keywords with the highest frequency of occurrence. The keyword co-occurrence network, illustrated in Figure 5A and detailed in Table 5, features nodes sized by keyword frequency and color-coded to represent distinct thematic clusters. Based on this analysis, the keywords can be categorized into five primary thematic groups. The red cluster focused on the risk stratification-based therapy, including “risk-factors”, “etiology” and “severity”. The green cluster emphasized the anti-RSV therapy, with terms like “pathogenesis”, “respiratory syncytial virus” and “infection”. The blue highlighted the respiratory support, featuring keywords such as “ventilation” and “oxygen-therapy”. The yellow focused on the clinical-practice guideline with keywords, such as “guideline” and “pulse oximetry”. The purple was mainly related to the trials of pediatric bronchiolitis with keywords, such as “double-blind”, “randomized-trial” and “multicenter”.

Table 4. Top 20 keywords co-occurrence network analysis.

ID	Keyword	Occurrences	Total link strength
379	Children	467	2,032
1022	Infants	401	1,806
286	Bronchiolitis	291	1,253
1227	Management	226	1,026
1027	Infection	170	783
1847	Respiratory syncytial virus	147	717
591	Disease	118	564
199	Asthma	118	545
2133	Therapy	119	542
2293	Young-children	105	542
2244	Viral bronchiolitis	97	489
577	Diagnosis	114	471
1891	Risk	79	378
1893	Risk-factors	67	349
1634	Positive airway pressure	65	340
2192	Trial	64	323
896	Hospitalizations	62	321
1505	Oxygen-therapy	61	310
987	Impact	59	289
1161	Length-of-stay	43	257

Figure 5.

Keyword network analysis. (A) Keyword co-occurrence network. (B) Time-overlapping keyword co-occurrence network. (C) Keyword citation burst analysis.

Table 5. Six clusters of co-occurrence network analysis.

Cluster	Items
Red	1st year	Palivizumab
	Age	Palivizumab prophylaxis
	Allergy	Premature-infants
	Association	Preschool-children
	Asthma	Preterm infants
	Birth	Prevalence
	Childhood	Respiratory syncytial virus
	Childhood asthma	Respiratory-tract infection
	Early-life	Rhinovirus
	Epidemiology	Risk
	Etiology	Risk-factors
	Exacerbations	Rsv bronchiolitis
	Follow-up	Severity
	Health	Symptoms
	High-risk	Syncytial virus
	Hospitalization	Syncytial virus-infection
	Hospitalized children	Tract infection
	Human metapneumovirus	Tract infections
	Infancy	Vial-infections
	Lung-function	Wheeze
	Morbidity	Young-children
Green	Activation	Adults
	Airway hyperresponsive	Bronchiolitis
	Cells	Dendritic cells
	Disease	Disease severity
	Epithelial-cells	Expression
	Gene-expression	Identification
	Immune-responses	Immunity
	In-vitro	In-vivo
	Infection	Infections
	Inflammation	Influenza
	Influenza-virus	Interferon
	Lung	Mice
	Nf-kappa-b	Pathogenesis
	Preterm	Respiratory syncytial virus
	Responses	Ribavirin
	Rsv	Rsv infection
	T-cells	Vaccine
	Viral load	Viral-infection
Blue	Acute bronchiolitis	Acute lung injury
	Acute viral bronchiolitis	Children
	Capa	Delivery
	Distress-syndrome	Experience
	Failure	Flow nasal cannula
	Infants	Intensive-care
	Intensive-care unit	Intubation
	Mechanical ventilation	Mortality
	Need	Noninvasive ventilation
	Obstructive pulmonary disease	Outcomes
	Oxygen	Oxygen-therapy
	Pediatric-intensive-care unit	Positive airway pressure
	Positive-pressure ventilation	Predicators
	Randomized controlled trial	Respiratory-distress
	Respiratory-failure	Status asthmaticus
	Support	Therapy
	Trial	Ventilation
Yellow	Agreement	Burden
	Care	Clinical-practice guideline
	Community-acquired pneumonia	Costs
	Diagnosis	Emergency-department
	Febrile infants	Guideline
	Guidelines	Hospitalizations
	Illness	Impact
	Implementation	Length-of-stay
	Management	Pneumonia
	Prospective multicenter	Pulse oximetry
	Serious bacterial-infections	Trends
	United-states	Us children
Purple	3-percent	Albuterol
	Controlled-trial	Corticosteroids
	Cystic-fibrosis	Dexamethasone
	Double-blind	Efficacy
	Epinephrine	Hospitalized infants
	Hypertonic saline	Moderate
	Multicenter	Nebulized hypertonic
	Oral dexamethasone	Placebo-controlled trial
	Randomized-trial	Salbutamol
	Syncytial virus bronchiolitis	Virus bronchiolitis

The time-overlay visualization map was presented in Figure 5B. Earlier studies, represented by darker nodes, predominantly focused on broad themes such as “efficacy”, “controlled-trial”, and “epinephrine”, reflecting the initial research emphasis on the treatment of pediatric bronchiolitis. In contrast, more recent trends highlighted in lighter nodes, such as “diagnosis”, “prevention”, and “guideline”, indicate a growing interest in preventive strategies, as well as diagnostic and guideline-oriented research, marking a shift from treatment-centered investigation toward proactive management and standardized care approaches.

As illustrated in Figure 5C, the burst intensity of the top 20 keywords ranged from 4.98 to 11.12, reflecting differences in their academic impact and research attention. Notably, “controlled trial” displayed the longest burst duration (2004–2013), while “hospitalizations” had the highest burst strength at 11.12. Notably, persistent bursts continuing into 2024 highlighted emerging research frontiers, including “burden” (2019–2024), “epidemiology” (2020–2024), “prevention” (2021–2024), “infections” (2021–2024), “oxygen therapy” (2022–2024) and “guideline” (2022–2024) had been more prominently concentrated.

Discussion

This bibliometric analysis of 1,370 publications provides a comprehensive overview of the global research landscape on the treatment of pediatric bronchiolitis, revealing significant shifts in research priorities and identifying key influential contributors in the field.

The United States is the leading contributor in this research field. Its prominence, supported by institutions such as Harvard University and the University System of Ohio, reflects a well-established research infrastructure, substantial funding for pediatric bronchiolitis treatment studies, and leadership in clinical trial initiatives. This finding may be attributed to the substantial healthcare burden in the USA, where approximately 100,000 hospital admissions for bronchiolitis occur annually, with an estimated cost of $1.73 billion (17). The American Academy of Pediatrics (AAP) serves as the primary source of clinical guidelines for pediatric bronchiolitis in the United States. In November 2014, the AAP published an updated clinical practice guideline in its official journal, Pediatrics, focusing on the diagnosis, management, and prevention of bronchiolitis in children. This guideline provides evidencebased support for both researchers and clinicians, reflecting the considerable influence of the United States in shaping standards of pediatric care (18).

Babl Franz E. has been identified as a highly influential contributor, leading other high-impact authors in both publication volume and h-index. Professor Babl Franz is the Group Leader of Emergency Research at the Murdoch Children’s Research Institute. His research focus is on multi-center randomized controlled trials and large observational studies in emergency conditions in children, including bronchiolitis treatment. For instance, a study indicated that high-flow oxygen therapy was associated with significantly lower rates of care escalation due to treatment failure compared to standard oxygen therapy in infants with bronchiolitis (19).

Research hotspots

Cluster 1 (red): risk stratification-based therapy

This cluster, characterized by keywords such as “risk-factors”, “etiology”, and “severity”, highlights a sustained research emphasis on risk-stratified management in bronchiolitis. While current guidelines primarily recommend supportive care and acknowledge high-risk conditions, clinical practice often deviates: many non-evidence-based diagnostic and therapeutic interventions continue to be used regardless of a patient’s individual risk profile (20). This discrepancy reinforces the need for clearer, evidence-based stratification to guide appropriate management. Recent guidelines outline established risk factors for severe bronchiolitis—including prematurity, age under three months, inadequate feeding or hydration, hemodynamically significant cardiac disease, bronchopulmonary dysplasia, and immunodeficiency (21). Additional factors, such as male sex, low weight on admission, tobacco exposure, and lack of breastfeeding, remain under debate (22). Progress is being made toward practical risk assessment: for example, Yan et al. developed and validated a nomogram to predict severe RSV-associated bronchiolitis in children under two years, showing good concordance with observed outcomes and underscoring its potential for early high-risk identification (22). Future multicentre studies are needed to refine and generalize such tools for broader pediatric use. Ultimately, advancing risk stratification through well-designed clinical studies can help minimize unnecessary treatments, such as albuterol, hypertonic saline, chest physiotherapy, and corticosteroids (20), while enabling more evidence-based management for infants with bronchiolitis.

Cluster 2 (green): anti-RSV therapy

This cluster is focused on the pathogenesis of pediatric bronchiolitis associated with RSV, featuring core keywords such as “pathogenesis”, “respiratory syncytial virus”, and “infection”. RSV is the most common cause of bronchiolitis (23). Following infection of the nasal epithelium, the virus replicates and triggers an amplified immune response, recruiting natural killer cells, lymphocytes, and granulocytes, ultimately resulting in airway narrowing and obstruction (7). In light of this pathogenesis, antiviral agents aimed at reducing viral load in bronchiolitis continue to be evaluated in early-phase studies. To date, however, no antiviral therapy has demonstrated clear clinical benefit in this setting, and none are currently recommended in clinical guidelines. Despite this, emerging agents such as the oral RSV fusion inhibitor rilematovir (NCT03656510) are under Phase 2 investigation and have shown modest but encouraging antiviral activity (24). Additionally, although other RSV-targeted therapies such as ribavirin have shown therapeutic benefits in certain pediatric subgroups (25), ribavirin is no longer recommended for routine clinical use due to its limited efficacy, particularly in immunocompromised populations (26). Overall, while current evidence does not support routine antiviral use in bronchiolitis, continued research, particularly into heterogeneity, may help identify subgroups that could benefit from targeted antiviral approaches. Future studies should further explore sources of outcome variation to refine treatment paradigms (27). Despite existing challenges, ongoing research underscores the potential utility of antiviral strategies in acute bronchiolitis and offers valuable insights for future clinical consideration.

Cluster 3 (blue): respiratory support

This cluster highlights oxygen therapy for pediatric bronchiolitis, with key themes including “ventilation” and “oxygen therapy”. Given the lack of specific etiologic treatments, management relies on supportive care to alleviate pulmonary and systemic symptoms (21). Respiratory support ranges from conventional low-flow oxygen therapy (LFOT) and high-flow nasal cannula (HFNC) to non-invasive ventilation (NIV) and invasive mechanical ventilation (MV) as needed (28). Current research focuses particularly on HFNC, which is believed to improve respiratory and heart rates by delivering positive airway pressure, reducing upper airway resistance, and clearing nasopharyngeal dead space (29). However, existing consensus guidelines offer limited guidance on HFNC use in bronchiolitis (30). Future updates should provide clearer recommendations on initiating and weaning HFNC. Additionally, research should identify which patients benefit most from HFNC and establish Achievable Benchmarks of Care for its use, offering hospitals a tangible target for optimizing HFNC utilization.

Cluster 4 (yellow): clinical-practice guideline & Cluster 5 (purple): trials

The yellow and purple clusters center on evidence-based guidance for managing bronchiolitis in infants. Supportive care continues to be the mainstay of treatment, with supplemental oxygen and target saturation thresholds highlighted across multiple national guidelines. Consistent recommendations advise initiating supplemental oxygen in infants with bronchiolitis if their oxygen saturation meets the following criteria: for infants ≥6 weeks, when SpO₂ is persistently <90%; and for those <6 weeks, or <12 months with underlying health conditions, when SpO₂ remains <92% (31,32). Further guidance includes: (I) avoiding the use of an oxygen hood or tent in place of a low-flow oxygen device for consistent delivery; (II) endorsing HFNC therapy as safe and more effective than low-flow oxygen for moderate to severe bronchiolitis; and (III) not recommending routine humidification with low-flow oxygen delivery (33). Collectively, these updated guidelines provide clinicians with evidence-based recommendations to guide clinical decision-making and improve patient outcomes, while underscoring the ongoing need for further rigorous research to strengthen the scientific foundation of therapeutic interventions.

Research trends

The rationale for supplemental “oxygen therapy” (2022–2024) in bronchiolitis draws on physiological principles, evidence from other respiratory conditions, observational data, and randomized controlled trials (34). For patients presenting with apnea or hypercapnia, continuous positive airway pressure may be considered in conjunction with oxygen therapy (35). Research on “prevention” reflects a shift in focus from treatment to prophylaxis. Pharmacologic prevention for bronchiolitis primarily targets RSV infection (36). In the absence of an approved RSV vaccine for infants (37), passive immunization remains the primary effective strategy, including maternal vaccination against RSV and the use of long-acting monoclonal antibodies. Available agents include RSV immunoglobulin intravenous (RespiGam^®) and intramuscular palivizumab (Synagis) (38). Both the AAP and the Paediatric Research in Emergency Departments International Collaborative (PREDICT) network incorporate palivizumab in their guidelines (18,31). A newer monoclonal antibody, nirsevimab, offers the advantages of single-dose administration at the start of the RSV season and improved cost-effectiveness compared with palivizumab (39). Emerging preventive approaches include maternal vaccines to protect neonates in early infancy, extended half-life monoclonal antibodies that provide rapid and sustained protection for at least five months after a single dose, and pediatric vaccines (21,38). Among RSV vaccine candidates, a maternal vaccine based on RSV fusion (F) protein nanoparticles has advanced significantly: a Phase 3 trial involving 4,636 participants demonstrated efficacy in reducing RSV-related hospitalizations (40). Additionally, several other maternal and pediatric RSV vaccine candidates are currently under investigation in preclinical through Phase 3 clinical trials (34). These preventive interventions offer immediate protection for high-risk infants and represent a proactive approach to controlling RSV infections on a broader scale, holding promise for reducing both the incidence and severity of bronchiolitis.

Limitations

Several limitations should be considered in this study. First, the bibliometric analysis was based exclusively on the WoSCC database. While WoSCC provides broad coverage, its sole use may introduce selection bias and limit the generalizability of the results, as relevant literature indexed in other databases such as PubMed or Scopus was not included. Second, restricting the analysis to English-language publications may have excluded important research published in other languages, while simultaneously overrepresenting the contributions of authors, institutions, and journals from English-speaking regions. Third, the omission of non-article document types, such as high-quality clinical practice guidelines and clinical pathways, may have narrowed the scope of the analysis and could potentially influence the findings of this study. Fourth, our search strategy focused on the specific term “bronchiolitis”. Although bronchiolitis is often classified as a viral lower respiratory tract infection, studies describing similar conditions using broader terms such as “viral lower respiratory tract infection” or “acute lower respiratory tract infection” may not have been captured. Consequently, some relevant publications could have been omitted. Nevertheless, this approach was adopted to ensure higher specificity of the bibliometric dataset and to avoid including studies related to other respiratory diseases that could confound the analysis. Finally, inconsistencies in data reporting, such as variations in author names and institutional affiliations across publications, may have affected the accuracy of author affiliation and collaboration network analyses. Future studies could enhance comprehensiveness by integrating multiple databases and incorporating a wider variety of document types.

Conclusions

This bibliometric study offers a systematic review of pediatric bronchiolitis treatment research published between 2014 and 2024, delineating major contributors, evolving hotspots, and emerging thematic directions. Five research clusters were identified, focusing respectively on risk stratification-based therapy, anti-RSV therapy, respiratory support, clinical-practice guideline, and clinical trials, collectively reflecting a shift toward prevention-oriented strategies and optimization of established treatments, notably oxygen therapy protocols. Moving forward, research efforts should prioritize multicenter trials to evaluate novel preventive interventions, particularly maternal RSV vaccination and long-acting monoclonal antibodies, and to inform the development of evidence-based clinical guidelines.

Supplementary

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Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.